Bump pbr from 5.2.0 to 5.2.1 (#5014)
Bump pbr from 5.2.0 to 5.2.1 (#5014)

Bumps [pbr](https://docs.openstack.org/pbr/latest/) from 5.2.0 to 5.2.1.
KWierso/treeherder,KWierso/treeherder,KWierso/treeherder,KWierso/treeherder